Evaluating craniofacial asymmetry with digital cephalometric images and cone-beam computed tomography.

INTRODUCTION: The aim of this study was to evaluate craniofacial asymmetry by using 2-dimensional (2D) posteroanterior cephalometric images, 3-dimensional cone-beam computed tomography (CBCT), and physical measurements (gold standard). METHODS: Ten dry human skulls were assessed, and radiopaque markers were placed on 17 skeletal landmarks. Twenty linear measurements were taken on each side to compare the right and left sides and to compare these measurements with the physical measurements made with a digital caliper. To acquire the 2D posteroanterior radiographs, an Extraoral Phosphor Storage Plate (Air Techniques, Chicago, Ill) was used as the image receptor with a Eureka x-ray-Duocon Machlett unit (Machlett Laboratores, Chicago, Ill). Three-dimensional imaging data were acquired from a CB MercuRay (Hitachi Medical, Tokyo, Japan). RESULTS: On average, the right side was larger than the left for most of the 20 distances evaluated in the digital 2D and the CBCT images, and there was poor agreement between the digital 2D images and the physical measurements (kappa = 0.0609) and almost perfect agreement (kappa = 0.92) between the CBCT and physical measurements when individual measurements were considered. CONCLUSIONS: Human skulls, with no apparent asymmetry, had some differences between the right and left sides, with dominance for the right side but with no clinical significance. CBCT can better evaluate craniofacial morphology when compared with digital 2D images.

Osteoarthritis of the temporomandibular joint and increase of the horizontal condylar angle: a longitudinal study.

OBJECTIVE: Our previous study of patients with unilateral temporomandibular joint (TMJ) osteoarthritis (OA) showed that the affected joints had greater horizontal condylar angle (HCA) compared with the contralateral unaffected joints. However, it was unclear whether the HCA changes preceded or were the result of OA changes. The aim of this longitudinal study was to investigate the relationship between HCA and OA progression. STUDY DESIGN: In total, 127 patients (with or without TMJ disorders) completed baseline and follow-up examinations (average time to follow-up 7.9 years). Generalized estimating equation models were used to account for correlation of observations within the same patients. RESULTS: (1) HCA was greater in OA-affected joints than in unaffected joints (P = .04). (2) Increased HCA at follow-up was associated with change in joint status from no OA to OA. (P = .001). (3) Baseline HCA value alone did not predict future OA diagnosis. (4) All OA changes in fossa/articular eminence morphology, and some combinations of condylar changes, were associated with a greater HCA. (5) OA diagnosis was associated with pain during maximum opening (P = .005) and pain history (P = .002). (6) Aging alone was not correlated with increased HCA. CONCLUSIONS: Clinical progression of OA preceded increases in HCA. HCA alone did not predict OA development.

Greater mandibular horizontal condylar angle is associated with temporomandibular joint osteoarthritis.

BACKGROUND: Research using magnetic resonance imaging analysis has shown that internal temporomandibular joint derangement is associated with significantly greater horizontal condylar angle. However, the association between osteoarthritic (OA) bony changes as shown on computed tomography and horizontal condylar angle has never been evaluated. OBJECTIVE: To investigate the relationship between mandibular condylar angle and OA degenerative changes. STUDY DESIGN: This is a retrospective study using cone beam computed tomography images and reports from 60 patients with unilateral OA degenerative changes and 43 control patients with no OA-affected joints. RESULTS: Condylar angles in the joints of control patients and the unaffected joints in OA patients were not significantly different. The mean horizontal condylar angle in the unilaterally OA-affected joints (29.5° ± 10.5°) was larger than in the contralateral unaffected joints (22.5° ± 7.7°) (P < .001). In the OA-affected joints, flattening and erosion of the articular eminence was associated with a greater condylar angle (P < .05). CONCLUSIONS: Moderate to severe degenerative temporomandibular joint change is associated with greater horizontal condylar angle.

Trabecular and cortical bone as risk factors for orthodontic relapse.

INTRODUCTION: Dental relapse of the mandibular incisors after orthodontic treatment is a common problem, and few risk factors have been identified. The purpose of this case-control study was to evaluate whether the amount or the structure of mandibular bone affects the potential for postorthodontic mandibular incisor relapse. METHODS: The subject sample was selected from the postretention database at the University of Washington. Subjects were chosen based on the availability of lateral cephalograms and mandibular periapical radiographs taken approximately 10 years postretention (T3). The mandibular incisor irregularity index (II) was measured on the T3 casts. Two groups were identified: subjects with the II greater than 6 mm (relapse or case) and those with the II less than 3.5 mm (stable or control). Once the case/control status was determined, the II was measured on models taken at the initial orthodontic examination (T1) and at the end of treatment (T2). Sixty relapse and 263 stable subjects were identified. Mandibular cortical thickness measured on both panoramic and lateral cephalometric radiographs was used to assess the amount of mandibular bone, and fractal analysis was used to analyze the trabecular bone structure around the mandibular incisors on the periapical radiographs. Logistic regression analyses were used to determine the association between dental relapse and significant bone parameters. The models were adjusted for potentially confounding variables (initial II, sex, age, and postretention time). RESULTS: The relapse subjects had a larger mean II at T1 and a longer postretention time than the stable subjects. The mean cephalometric mandibular cortical thickness was significantly smaller in the relapse group than in the stable group at T1, T2, and T3. There were no statistically significant differences in the trabecular structure of bone, as measured with fractal analyses, between the relapse and stable groups. CONCLUSIONS: These results indicate that patients with thinner mandibular cortices are at increased risk for dental relapse.

Mandibular inferior cortical bone thickness on panoramic radiographs in patients using bisphosphonates.

OBJECTIVE: The goal of this study was to detect dimensional changes in the mandibular cortical bone associated with bisphosphonate (BP) use and to correlate measurements of the cortical bone with the cumulative dose of BPs. STUDY DESIGN: Mandibular inferior cortical bone thickness (MICBT) was measured under the mental foramen on panoramic radiographs of patients with and without bisphosphonate-related osteonecrosis of the jaws (BRONJ) taking BPs and controls. RESULTS: Patients with BRONJ had the highest mean MICBT (6.81 ± 1.35 mm), compared with patients without BRONJ taking BPs (5.44 ± 1.09 mm) and controls (4.79 ± 0.85 mm) (P < .01). Mean MICBT of patients with BRONJ was significantly higher than that of patients without BRONJ taking BPs. There was a correlation between MICBT and cumulative dose of zolendronate. CONCLUSIONS: Measurement of MICBT on panoramic radiographs is a potentially useful tool for the detection of dimensional changes associated with BP therapy.

The impact of ethnicity, gender, and marital status on periodontal and systemic health of older subjects in the Trials to Enhance Elders' Teeth and Oral Health (TEETH).

BACKGROUND: Few studies have examined the association between periodontitis risk, gender, and marital status in older adults. The purpose of this study was to assess if the oral health status of older subjects could be explained by differences in: 1) marital status; 2) gender; and 3) ethnicity. METHODS: Clinical and radiographic periodontal oral conditions were studied in 701 older subjects from the TEETH clinical trial. Medical conditions as well as ethnic and marital status and smoking habits were considered. RESULTS: A total of 89 married couples were identified; 40.7% of these were of European descent and 48.1% of Chinese descent. The mean age was 67.7 years (SD +/- 4.7). The men were older than the women (mean difference: 1.5 years, SD +/- 4.6, 95% confidence interval [CI]: 0.5 to 2.5, P<0.01). No significant differences in periodontal conditions were found between spouses or by marital status. Chinese descent was associated with a higher risk for periodontitis, regardless of marital status (odds ratio: 1.5, 95% CI: 1.05 to 2.04, P<0.03). CONCLUSIONS: 1) Married couples have similar social habits, similar oral health perceptions, and similar patterns of periodontal disease. 2) Dental studies including married couples do not bias data for married subjects as such. 3) Marital status has a limited impact on periodontal health but may have a greater impact on several systemic conditions, especially in widowed, divorced, or never married women. 4) Older Chinese subjects perceive themselves as being at lower risk for periodontitis but have more objective signs of periodontitis than older subjects of European descent.

Clinical application of spiral tomography in anterior implant placement: case report.

BACKGROUND: Placement of endosseous dental implants in edentulous areas of the anterior maxilla poses a unique challenge due to variations in the amount of residual alveolar bone. Implant position becomes crucial in cases demanding high esthetic results but possessing minimal ridge width or in cases requiring augmentation. Recent advances in spiral tomography have allowed for more precise planning and placement of endosseous implants in these challenging areas. METHODS: The purpose of this report is to describe a series of clinical cases in which spiral tomography was utilized in the planning and placement of endosseous dental implants. Two cases will be described utilizing initial spiral tomographic radiographs for implant planning and surgical guide fabrication, followed by post-insertion tomography to evaluate the results of implant position and inclination. RESULTS: Preimplant spiral tomograms revealed that the initial prosthetic trajectory through the proposed incisal edge of each tooth replacement would result in a final osteotomy site that would compromise the overall thickness of the facial cortical plate. After adjusting for magnification and distortion factors, new prosthetic/surgical trajectories were fabricated into the surgical guide, and this information was utilized to prepare the final implant osteotomy site. This adjustment resulted in 2 mm of residual crestal facial bone postimplant insertion, which became wider at more apical measurements. These findings were verified in the postimplant serial tomograms. CONCLUSIONS: Spiral tomography was a valuable adjunct in the treatment planning phases of endosseous dental implant placement especially in cases with minimal crestal width, high esthetic demands, or where exact implant placement is critical for successful treatment outcomes.

Mandibular cortical bone evaluation on cone beam computed tomography images of patients with bisphosphonate-related osteonecrosis of the jaw.

OBJECTIVES: The objective of this study was to develop a technique for detecting cortical bone dimensional changes in patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ). STUDY DESIGN: Subjects with BRONJ who had cone-beam computed tomography imaging were selected, with age- and gender-matched controls. Mandibular cortical bone measurements to detect bisphosphonate-related cortical bone changes were made inferior to mental foramen, in 3 different ways: within a fixed sized rectangle, in a rectangle varying with the cortical height, and a ratio between area and height. RESULTS: Twelve BRONJ cases and 66 controls were evaluated. The cortical bone measurements were significantly higher in cases than controls for all 3 techniques. The bone measurements were strongly associated with BRONJ case status (odds ratio 3.36-7.84). The inter-rater reliability coefficients were high for all techniques (0.71-0.90). CONCLUSIONS: Mandibular cortical bone measurement is a potentially useful tool in the detection of bone dimensional changes caused by bisphosphonates.

Number of teeth and residual alveolar ridge height in subjects with a history of self-reported osteoporotic fractures.

The purpose of this case-control study was to determine if elderly subjects with a history of osteoporotic fractures have fewer teeth and greater residual ridge resorption than subjects without such fractures. Patients older than 60 with a panoramic radiograph were invited to a phone interview. Information was obtained regarding fracture history, smoking, and hormone replacement therapy (HRT). The number of teeth was obtained from the panoramic radiograph. The residual ridge height of the edentulous mandible was measured at the site of the mental foramen. Multiple regression models were used to assess the association between fracture status and number of teeth or residual ridge height (controlling for age, gender, HRT, smoking, height and weight). Cases (n=93) were individuals reporting osteoporotic fractures (fractures occurring after minor impact). Controls (n=394) were individuals reporting traumatic fractures (n=105) or no fractures (n=289). Fracture status in this population affect neither the number of teeth nor the residual ridge height. In the regression model, the variables that had a statistically-significant effect on the number of teeth were age (p<0.0001) and smoking (p<0.0001). There was a dose-effect of smoking on the number of teeth. In the regression model, the variables that had a significantly-significant on residual ridge height (n=95 edentulous subjects) were age and gender. Our conclusion was that in elderly dental-school patients the number of teeth and residual ridge height were not influenced by fracture status. Age and smoking had the most influence; there was no effect from HRT. The clinical implication is that a history of osteoporotic fractures is not an important cause for tooth loss and residual ridge resorption in an elderly dental-school population.

Signs of carotid calcification from dental panoramic radiographs are in agreement with Doppler sonography results.

BACKGROUND: Duplex ultrasonography (DS) is a frequently used noninvasive method for assessing carotid artery stenosis. The level of agreement between panoramic radiographs (PMX) findings of radiopacities in the area of C3-C4 and DS results has not been established. AIMS: (1) to examine the level of agreement between DS results and PMX signs of carotid calcification and (2) to evaluate the association between periodontitis and DS results. MATERIAL AND METHODS: Eighty-three subjects who had received a DS assessment at the University of Washington Medical Center within 36 months volunteered for a periodontal examination, including assessments of probing pocket depth (PPD), attachment level (PAL), evidence of bleeding on probing and bone loss from PMX. Two examiners independently analyzed the radiographs for evidence of carotid calcifications. The distance between the cemento-enamel junction (CEJ) to bone level (BL) CEJ-BL was used to assess alveolar bone loss as a criteria for periodontitis. RESULTS: Twenty-nine subjects (34.9%) presented with positive DS readings. The Mantel-Haentszel common odds ratio estimate for a positive DS score and periodontitis (> 30% of teeth with distance CEJ-BL > or = 4.0 mm) was 38.4 (95% CI: 10.6-138.7, p < 0.0001). For nonsmokers only (n = 72) the odds ratio was 43.0 (95% CI: 16.7-1178.0, p < 0.0001). Evidence of bleeding on probing was 16% of sites both in the DS-positive and -negative subjects. Subjects with a positive DS result had significantly more teeth with clinical evidence of attachment loss > or = 5.0 mm (p < 0.001). The odds ratio of having periodontitis (CEJ-BL > or = 4.0 mm at > or = 30% of the teeth) and medical records confirmed diagnosis of either a stroke or an infarct or both was 7.8 (95% CI: 2.6-23.8, p < 0.001). CONCLUSIONS: Subjects with positive DS readings of the carotid arteries due to calcified arterial plaque are accurately detected by means of conventional PMX. The likelihood of being DS positive and having radiographic evidence of periodontitis is high. A dose-response relationship between the extent of carotid calcification and severity of periodontitis was demonstrated, supporting the hypothesis of an association between periodontitis and cardiovascular diseases.